I pulled out the common functionality to be evaluated once, and used array()
instead of asarray() (they are equivalent, but array() is faster).

This is a partial fix to sympy#14671. It isn't as fast as it used to be yet. I
don't know how to make the decorator faster, other than code generating the
array wrapping directly, which would require improvements to lambdify to work
(lambdify would need to be able to code generation full Python functions).